The term ‘dendrimer’ is derived from ‘dendro’ (meaning tree-like in Greek)+polymer, and refers to an oligomer or polymer having a large number of branches arranged in a regular structure as the name suggests. Dendrimers are also called “arborols” meaning tree in Latin) or cascade polymers. The dendrimers have a polydispersity of about 1, an approximately spherical shape, and a large number of functional groups in the outermost portions thereof, and thus show unique chemical and physical properties.
Due to such unique properties, dendrimers have been spotlighted as ideal materials in various industrial fields. Typical examples of such industrial fields include additives, powder coatings, blend materials, delivery devices, liquid crystals, functional carriers, catalysts, sensors, multi-functional crosslinking agents, etc.
More recently, application of dendrimers to medical and pharmaceutical fields has drawing attentions. In this context, dendrimers may be provided in various forms having a wide variety of applicability, like carbon nanotubes (CNT). In addition, as shown in FIG. 2, dendrimers may be applied in various forms, and thus are known to be superior to nanotubes or fullerenes.
As revealed by search of reference publications or DECHEMA data, approximately 200 institutes or researchers are conducting studies on the dendrimers. For example, their studies may be classified into the following three categories: Voegtle's model [polyamidoamine (PAMAM) dendrimers], Frechet's model (ether-bonded dendrimers) and Tomalia's model (ester-bonded dendrimers). The dendrimers have been commercially available as electric/electronic materials, catalysts, etc. More recently, carbosilane dendrimers suggested by van der Made are being studied.
Although dendrimers have been studied actively as mentioned above, studies thereof for environmental application are still in early stage. Mamadou Diallo of the California Institute of Technology has studied about treatment of anionic perchlorate with poly(amidoamine) (PAMAM) dendrimers and treatment of heavy metals, such as copper, using a dendrimer-membrane. And, Yinhui Xu of Auburn University has developed a method for treating copper and lead with a dendrimer from contaminated soil.
However, most of the studies are merely in the early stage for environmental application of previously commercialized dendrimers. Moreover, such previous studies use filtration of the treated dendrimers with a membrane, and thus are not cost-efficient. In Korea, there is no study about application of dendrimers in the field of environmental industry, and studies of dendrimers are limited mainly to some industrial fields, such as adjuvants for medical or biochemical products, display materials, or electric/electronic devices.
Meanwhile, in the iron and steel industry and manufacturing industry, industrial water has been treated to remove various types of contaminants incorporated during the processes. The contaminants are removed from industrial wastewater by using a process including agglomeration, precipitation or filtration. Such an agglomeration/precipitation process treats industrial wastewater by converting the contaminants into crude floccules with a coagulant and an agglomerating agent and by carrying out solid/liquid separation in a precipitation unit. However, because the resultant contaminant floccules show a low precipitation rate in the precipitate unit, a large-scale precipitation unit is required to collect the agglomerated floccules. Therefore, such a process has a disadvantage in that it requires high investment costs for the equipment and site to build a plant. In addition, some chemicals used in the agglomeration/precipitation process may cause secondary environmental pollution, and the precipitation sludge is not amenable to recycling. As a result, there is another disadvantage in that the collected contaminants and the agglomerating agent are discarded together.
According to the related art, an apparatus for collecting magnetic contaminants using magnetic power was developed to remove the magnetic contaminants floating on wastewater, such as one discharged from the iron making industry. However, in the case of wastewater from the iron making industry, the magnetic contaminants may have insufficient magnetic properties, particularly when they have a small particle diameter or low magnetizing capability. In this case, it is difficult to remove the contaminants with such a conventional magnetic separation system. Due to this, it is required that the contaminants are passed through the magnetic separation system several times. Therefore, when purifying wastewater containing magnetic nanoparticles, a complicated process is required, and a large area of land is necessary to build the processing systems, thereby resulting in marked limitation in the place where the process is carried out.